This is a sample app that demonstrates how to capture screenshots based on the MediaProjection API. More on the API can be found in https://developer.android.com/reference/android/media/projection/package-summary.html Clone and import the project in Android Studio. No special dependencies and extra libraries required. Note that in order to run the code you need to create a device running Lollipop and above.
As of this writting I am getting a black screen when running the app in an emulator running Android 6.0 and lower versions. The screen captures are working successfully in emulators with Android 6.0.1 and later versions (see issue 5 for additional info). Also, Android 5.1 has a bug when we check "Do not show again" box, please refer to https://code.google.com/p/android/issues/detail?id=159613.